Error compensation model by variational mode decomposition method for precision angle encoders

Abstract Angle encoders enable high-accuracy and reliable angular measurements by the signal interpolation of light interference, in which the signal error plays an important role in limiting the measurement accuracy. To improve the accuracy of angle encoders, an error compensation model that extracts the signal error feature and further reconstructs the signal is established by variational mode decomposition (VMD) method. The VMD is used to adaptively decompose the error data into k intrinsic mode function (IMF), improving the signal error extracting efficiency. By analysis of the information contained in the IMF, an error compensation model is established, and the signal could be reconstructed by the error compensation to improve the measurement accuracy. It is found that, after the compensation, the mean, peak, and standard deviation of the error, could be reduced to 0.1739″, and 0.6846″, respectively.